Introduction

ABSTRACT: This introductory talk at the Cosmic Questions conference
(presented by Joel Primack) summarized some earlier pictures of the universe and
some pictures based on modern physics and cosmology.

Today cosmologists are telling each other at every
conference that this is the golden age - or at least a golden age - of
cosmology. It is a tremendously
successful period because we are seeing the death of so many theories! Back in 1984 George Blumenthal, Sandra
Faber, Martin Rees, and I published a paperin which we described the theory of
cold dark matter and worked out two versions of it in some detail. A
couple of years later Jon Holtzman, a student with Sandra Faber and me, worked
out 96 different variants of the cold dark matter scenario. Now, I am proud to say, all but one of them
are pretty convincingly ruled out. But
the one that is left (which is closely related to one of the two in our
original paper) may actually be right. That is fantastic progress!

Now as we are trying to put
together a picture of the whole universe, its origin, evolution, structure, and
future - that is what cosmology is all about - the question arises whether this
has any broader implications. Does it
matter to people as people, and not just as cosmologists (or other kinds of
scientists)? I think it does, but that
is for you to decide. I hope this
Cosmic Questions volume helps.

What I am
going to do in the rest of this paper is to try to explain cosmology, not in a
technical way, but rather through stories and pictures, especially
pictures. That is the way most people
throughout history have experienced cosmology.
Not as a series of scientific theories that are put forward as hopeful
explanations to be tested against data - which is what we do as professional
cosmologists - but rather as an understanding that one can grasp and visualize:
a picture.

The joke about cosmology
used to be that it was the only field of science in which the ratio of theory
to data was infinite. But now the
situation is reversed, and the ratio has gone to almost zero. Today data is
flowing in so fast from new instruments that the question is whether a single
one of the current theories can survive. If one theory survives the present
onslaught of data, it will be revolutionary.

The advent of a new
cosmology can radically change the culture of its time. In particular, the scientific revolution of
the 16th and 17th centuries helped end the Middle Ages
and bring about the European Enlightenment.
But it also split scientific knowledge from human meaning, which was at
the time largely determined by religion.
How will a new picture of the universe at the turn of the 21st
century affect global culture? That is
one of the questions explored in this Cosmic Questions volume.